Style/scheme-specific error page
Short, concise description of the idea
I think invalid URLs within a specific journal should conform to the site's BML scheme and a user's S2 style.
Full description of the idea
Currently, if you try to visit a page in someone's journal that LiveJournal does not support (e.g., http://www.livejournal.com/community/suggestions/2003/00/00/), you get an unstylized error page. It would be nice if such pages appeared in the appropriate BML scheme, and if S2 styles had the ability to override said BML scheme; this way, the pages would still be part of the user's LiveJournal. Perhaps a class ErrorPage, extending Page?
If any of this was unclear, kick me. Alternatively, comment.
An ordered list of benefits
A BML/S2-icized error page would look better, for one thing. You'd still be at LiveJournal; you'd simply have arrived at a page without meaningful content.
A BML/S2-icized error page could/would have links to the correct pages. (Granted, if the system could guess exactly what page you wanted, it would in most cases simply give it to you - one exception being http://unpaidusername.livejournal.com/; but the BML/S2-icized error page would link to your journal and userinfo, and probably to your friends page and calendar; i.e., to content.)
There'd be a more elegant solution to Bug #128: if you tried to visit a non-existent or non-public friends group page, you could simply receive an error page ("Friends group foo does not exist or is not public").
An ordered list of problems/issues involved
It might be less clear that you've reached an error page and not a page with content?
When such error messages become translatable (if they aren't already), would they be served in the journal language or the language the site is being viewed in?
A user with S2 could do funkiness to make it unclear that a page is an error page. I don't see that as a serious problem, though; if they don't want their journal to be coherently navigable, that's their right.
If you have any more thoughts, comment! :-)
An organized list, or a few short paragraphs detailing suggestions for implementation
For the existing error pages (I don't know how many there are, unfortunately), convert them to BML format. I doubt that's difficult, though obviously I could be wrong.
Create a class ErrorPage that extends Page, that could be used to override the BML error page if the journal is that of a paying user with S2. If error pages are ever shown because the style is incomprehensible to LJ (I know that can happen in S1, e.g. if you delete everything in the style, but can that happen in S2?), then revert those error pages to the BML format.
Finally, look at pages that aren't currently error pages, and see if they should be. For example, as I mentioned above, friends-group-specific pages for nonexistent/nonviewable friends groups? Thoughts?