This can be a life saver for webmaster and editors. For example; you have a download (program) website you must monitor some big websites (like download.com). And day to day there is new builds for a program. Programs on your website need to update daily.
BTW, When I use a rss feed there is always updates on download.com or softpedia.com and I cannot monitor all of them, if this program on my website or not. It could be great if I can type some keywords to RSS feed and feed will promp me if download.com has update a program that my website has it (on keywords).
Keywords can be fetched with some sql queries (program names) and can be added to RSS feed fetcher's keyword database. Of course it is useful for some users who wants to use latest programs.
And latest note: This can be good, if rss program has a timeout promp. I mean if your website down, rss fetcher program can't fetch anything. If can't fetch anything in 30 sec. it can promp you "Hey your website is down! Do something". This could be a good thing who wants to stay alive his/her website. Thanks How-To Geek Forums!