[tabtab]

Maybe an alert system that monitors selected websites for certain content (key words) or even lack of content, such as outages. RSS can potentially do this, but you have to accept lots of content to filter it locally (client-side), and its not portable. Have a smart-phone app, emails, and web-only interface as options for receiving notices.

[PaulHoule]

I am working on something kinda-sorta like this, but I'm not so sure how to productize it. I think the industry as a whole has been held back by the "phone app" phenomenon because it discourages people from taking full advantage of the power of PCs.

The trouble is that you have to have an "irrelevance model" and that may be even more user specific than a relevance model. (For instance, anything about Apple is in my irrelevance model for HN) The irrelevance model may be more important than the relevance model because 99.9% of everything is junk, so the problem of finding actionable "news" is like making glasses that let you look at the sun.

[tabtab]

Good filters have both "include" words and "exclude" words. It could also have something like Outlook's filtering "wizard" that allows fairly complex logic trees. But one has to be careful to not get carried away early in a project.