Ron, you have some great suggestions. Smartfeed needed a separate interface because it also needed to work for guests. I wrote the Digest mod to be accessible only to registered users. I suppose that could change too, although I don't particularly want the overhead of maintaining a separate table of non-registered email addresses. In any event if ONLY registered users can get digests then it makes a lot of sense to put the interface into the User Control Panel. The downside is that it becomes hard to discover the digest feature. When it is on the main menu, it becomes hard to miss. It could perhaps be in both locations, with the main menu redirecting the the User Control Panel.
I also wonder if I need to rethink digest frequency. Under phpBB 2 is is either daily or weekly. I've had requests before to have it for shorter or longer time periods. Smartfeed allows a lot of flexibility from 15 minutes to no time limit, with the Administrator being able to set a policy limits time ranges, number of posts in a feed etc.
I have also been studying the cron feature in phpBB 3. It is not a real cron in that it run jobs at set times, although that will be a feature in phpBB 3.2 apparently. But it does allow jobs to get run when someone happens to access the board. For very low trafficked board a daily digest might not appear until days later when someone comes to the board. So I think the best thing is to have a ACP switch. For pseudo-cron only, administrators would have to live with the fact that digests may be delivered very late. For those who take the time to actually create a cron and run it from it, digests would arrive at a predictable time of day. I would need to keep track of when a user last was sent a digest.
For text digests, if they are to be supported I might want to rethink the implementation. Currently forum and topic names are delineated with lots of <<<<< and >>>>> characters. It might make sense to instead have something like:
Begin forum: x
Begin topic: y
End topic: y
End forum: y
Smartfeed also has a lot of flexibility sorting posts. I should probably extend it to the digests mod, putting posts in time sequence regardless of forum and topic, etc. Those not familiar with Smartfeed may want to look at its user interface for phpBB 3 and tell me what features they think would be valuable:
I suggest logging in to see additional controls, ID: Smartfeed Tester, password: smartfeed
I don't know much about wireless devices, but perhaps I should support wireless markup language or something.
As for merging Smartfeed and Digests, it may be possible, but may not be advisable. In theory since Smartfeed returns posts as XML, I could take advantage of XML Stylesheet technologies and push content through a stylesheet, rendering either text or HTML that way, as opposed to coding it. There are some problems. PHP support for XSLT is rather weak and presumably I would have to support the lowest common denominator. PHP 4.3.3 is the lowest version supported. I cannot assume that XSLT is installed so I would probably need a third party library to do the translation.
So many pathways, but the design really depends on what people need.