Well, I would say the latter seems the better of the two. However, overall the search engine optimization rank does not come off sounding entirely cohesive when sounded out in full. At least IMO, not quite likesearch engine rank. ...But then again, as far as word association, people do tend to group the short form "SEO" with "RANK" The word "the", I would say, also detracts form the overall name in this case. Overall, it's a fairly decent domain name, I suppose (the second one, that is). .