This is a good topic, and I wish I could write more.
The topic of how to reach the SME community is of critical importance. And sales teams are clearly a shortfall of the major SE who own the ad inventory. This is why relationships with the major telcos (exp: Bell South) and with the agencies (SMEglobal -Dex/Interland)are important to SEs. It is a "feet on the street strategy" to sell advertising to SMEs that is appealing to the SEs.
Even in employing these traditional sales tactics, the major SEs themselves also understand the value of direct marketing. How many direct mail pieces have you recieved from O and G? Many. Register a URL, get a mail piece. We have collected dozens of such pieces.
Direct mail is going to be important to SME adoption of Internet advertising. We have tried it, with modest success, and we are often approached by traditional direct mail houses and data aggregators looking to partner in sending direct mail to SMEs to sell Internet advertising. We also see many partners inquiring about our top verticals and top target cities because they intend on using direct mail.
When attempting to reach a massive SME marketplace that is not predisposed to understanding or tracking down Internet inventory providers, direct mail can neatly augment a customer acquistion strategy.
Don't know about the UK, but here in the US, the old standard for direct mail campaign responses used to be 1% (I have not checked this data in a *long* time).
I'd imagine that considering that the Internet is "dismissed" by many as a source of income for their business, especially those on a local only level, that it would be expected to be lower than the standard unless highly targeted.
But, total speculation on my part. ;) I should be working...