Regular readers will probably have noticed that I'm currently a bit obsessed with Social Bookmarking sites. In the recent past I've posted on del.icio.us, BlueDot and Ma.gnolia. Part of the reason for this obsession is that I want all my bookmarks in one place and to have a custom interface to them on geekglue.com (you can still see my old system in the links area). Which brings me to my problem. Working with the BlueDot API (the del.icio.us version) I realised that none of these services offer a bookmark based search facility. You can search by tags but not on the title or content of a bookmark. For example, I currently have 391 bookmarks, 41 tagged as actionscript. I can easily select a second tag to further filter my actionscript bookmarks. But there have been a number of recent occasions when I knew the bookmarks title but was a bit vague on it's tags (partly this is poor tag organisation; what can I say it is a work in progress). What would be great is to be able to search bookmarks rather than tags. For most people it's not really a problem because they maintain a relatively short collection of bookmarks. But as soon as your largest tag group starts to exceed 20 bookmarks (2 pages on BlueDot). Then you'll start looking for a bookmark search button. Being able to select the number of bookmarks displayed per page could help. But really thats just postponing the inevitable primordial urge : the urge to search.
As Mohit points out, see comments, a search method is available through the BlueDot SOAP API. My bad for not following through my research properly. It isn't entirely clear in the documentation but you can search purely using a keyword (i.e with tags = NULL; thanks Mohit for the clarification).