> Is a campaign at this level actually worthwhile
Of your concerns, it is ROI that tops all. If you get every single piece of ROI, from a heavily opto-ed site for AJ/TEOMA, would you make money?
Now be realistic, with a sponsored listing, even some of the best promotors around, which use the premium listings on SE's get around a 20% click per SERP view, then how much off that converts to INCOME, is the critical component. (a considerable number of Joe Blogg searchers are aware to an extent that the premium listings are paid for - hence not their on the relitiveness to the search-term - certainly worth considering this).
Their is money to be made on all search engines with the correct sort of opto-marketing approach, though the ROI curve, is dependant on the traffic and the search demographics of the search engine, and AJ/teoma, seems to be a little more feminine than most.
Personally with Teoma/AJ i would be tempted to roll out a site aimed at teoma/AJ algo, moving towards the authoritative hub structures which it views the net. And get the #1 Position for the vast-majority of KW's, to see what it is like at the top with minimal expediture. Then decisions can be made - hopefully while teoma/AJ are growing in unique visitor numbers.