Tag search engine...
Gataga is a new search engine that searches items according to their tags (keywords), such as tagged URLs (e.g. del.icio.us) and tagged photos (e.g. flickr). It also includes RSS feeds on the tag searches, so you can keep an eye on your favourite search terms without having to go back to the engine each time.
Interestingly, it has a mobile interface (XHTML), which you can view here in your regular browser. Note the apparently pointless step of asking whether you want to search photos or blogs, before giving you the text box. This seemingly small step could be a big block for mobile users who aren't going to hang around for a new page to download each time they use the service.
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