If you need extra push for your business, then you should seriously be looking at Google AdWords first. Yahoo is a good second choice to consider, but for most people, you really don’t need to consider MSN at this time.
MSN has lost so much traction in the world of pay per click, that I have to say I just don’t think that investing in the set up and management of a program there warrants the expense. There is a very narrow market there and the return on investment is simply not happening.
It used to be that for the majority of accounts you would receive nearly half of your AdWords conversions on Yahoo and then again about another half of what you got on Yahoo on MSN, but now the figures are even more dismal. Here is just one very pointed example for one high tech client:
Google AdWords: 4725 clicks, 209,254 impressions 2.26% CTR
Yahoo: 1536 clicks 87,136 impressions 1.76% CTR
MSN: 69 clicks 1,970 impressions 3.50%CTR
This program is just showing on search and search partners, no clicks are coming from content. Clearly MSN simply does not have the technical search traffic for industrial and high tech customers that Google and Yahoo do.
If you are selling entertainment products, beauty products MSN may still be a solution for your needs but if your PPC program is for technical and business don’t waste your time with MSN at this point.