Tip: for customizing on Modern Site shared with B2B guests, use SPFx and not PowerApps

In Modern SharePoint, the citizen-developer way for page customization is through PowerApps (instead of the dreaded InfoPath approach). This works out fine..., unless your site is shared with external Azure AD B2B guests. A condition for PowerApps usage is namely that the logged-on user is licensed for a PowerApps Plan. For regular member accounts this license is typical provisioned on onboarding time. For guest accounts you cannot trust that each of them has a PowerApps license already themselves, and then access to use the PowerApps customization requires that a license is assigned in the inviting tenant. But probably you do not want to assign licenses in the inviting tenant to Azure AD B2B guests. After all, one of the charms of the Azure AD B2B model is that for each paid Azure AD license the organization is entitled to invite up to 5 guest accounts without additional costs.

The result for guests that do not have a PowerApps license themselves, is a broken user experience. Instead of a working custom control / form in the SharePoint page, the guest site visitors are confronted with a notification about need for PowerApps Plan license:

A minimal approach to at least avoid the broken UI experience would be to hide the PowerApps control for guest accounts. But also this is not possible: audience targeting on arbitrary webparts is not supported in Modern Pages, see Overview of audience targeting in modern SharePoint sites.

In a SPFx control you can utilize an alternative for audience check, by check on permission group, or check on account type (member or guest). A code example of this approach: Show and hide SPFx Webpart Content based on user permission.

However, when using SPFx for page customization then you’re not subject to additional licensing on top of SharePoint license. So it would not even be needed to hide the control in case logged-on user is a guest account....

Conclusion: if you plan to share a Modern SharePoint site with external guests, then better not use PowerApps for customizing a page that is accessible for guest accounts. Better approach is via SPFx, and accepts this requires coding skills iso no/low-code.

Options considered for extending Stream Live Events with live chat/questions capability

With the recent GA of Stream Live Events, Microsoft delivers a low-entry option to easily setup company-internal webcasts. All you need in addition are on the webcast producing side: 1) recording equipment - camera + audio, and 2) an encoder solution to transmit the recording inputs into the Live Events endpoint. The camera + audio options vary from the onboard webcam + microphone of a laptop, USB-based externals, upto high-end studio-quality equipment. For Stream Live Events handling the sophistication on the producing input side does not make a difference, the inputted RTMP(S) signal is from input endpoint processed the same. Whether an organization also needs some additionals on the consumption side depends on the audience side plus the internal network capacity. Watching a Live Event instantiates an individual / unicast stream per event viewer. Under assumption that the company network is sufficient scaled for nowaday cloud solutions usage, it is feasile to simultanuous watch a 'LIVE' Stream event per network location upto a maximum of few hundreds. In case of bigger audience, Microsoft states that it is needed to reduce the network load via a video distribution approach through a SDN/eSDN solution.

In its first released version, Stream Live Events capabilities are focussed on the core streaming + playing aspects. Business demands on a webcast typical go beyond that. The biggest additional demand is for interaction between the webcast audience and the presenter. Thus a chat window in which individual attendees can submit their questions, and that the presenter can follow + respond on. It is on the roadmap of Stream Live Events to deliver this (note: Stream recent delivered 'quizzes/ polls' capability, but this is targetted at inserting in already recorded videos for a.o. training purposes; not for dynamic interaction with live streaming), but not out-of-the-box delivered nowadays. However, with Office 365 as underlying platform you have as event developer a feature-rich toolbox at hand in which you can deliver yourself a webcast experience in which viewers have the live stream and chatbox combined, via no-code or low-code approaches. The hosting platform of such landingspage is naturally SharePoint Online....; as every created Stream Group is effectively an Office 365 Group, it has an own SharePoint Modern Team Site provisioned. The persons authorized to this site is the same audience that are permitted to join the scheduled Live Event. Create in this site a new page to function as the webcast entrance, and select the '2:1 columns' layout. In the left column embed the Stream Live Event instance - one gets this from Stream via 'Share' and then pick the 'Embed' option. With this setup, all left is to extend with chatbox / questions input control. There you have multiple options. One is to utilize the rich capabilities of Yammer, and embed a Yammer channel on the page. This gives you immediate a 'chat-like' experience, in which one can enter questions, semi-live follow the inputs / chats of others, respond on inputs of others. This immediate visibility of all the responses of ones peers may be unwanted, e.g. due potential sensitivity. In that case an alternative setup is to capture the inputs in a SharePoint list in the site, and only grant the webcast facilitators the authorization to view all received inputs. The webcast attendees submit their questions and feedback via an input form embedded on the SharePoint page. For this on sublevel again multiple alternatives are available. You can embed the out-of-the-box NewForm of the list; customize the NewForm via PowerApps; a MS Forms instance that via MS Flow sends the input to SharePoint List; or build a custom control via SPFx or even as a chatbot via Azure Bot Service. Of these options all except for the latter 2 are no/low-code 'mash-up' compositions, that deliver on the needed job. The decision-weighing between them is mostly on the user-experience and branding, see screen impressions of the various options.