I've been getting emails from people claiming to be interested in buying ad space links on one of my sites. It's a bit of a rubbish site and I've not done anything on it for several years. Seems strange that suddenly several people want to buy ads on it. I thought maybe the site has suddenly jumped in SERPs or something, but that's not the case.
Then I find that all these people are writing from email addresses at relatively new domains such as outsourcedcontenttoday.com and HomeOutreacher.com (the owners of whom all seem to be hiding behind WHOIS privacy)
Is this a scam to confirm a working email address for the webmaster before sending spam? Or is there something else at play?