[marttt]

Just the typical thing: while adding a bookmark, when I start typing in the first letters of a tag (e.g. "hack" for "hackernews"), Pinboard is offering a drop-down menu with possible matches. Linkhut didn't have this last time I checked. It is maybe not a big issue, though -- possibly, relying on your own memory (not programmatically offered suggestions), your tagcloud may get less messy over time; you'll end up with a smaller amount of tags, which may be a good thing at times.

I think I like 'em both, Pinboard and Linkhut, though.