qth.com definitely sends you an email...it'll usually have the  title of 
your listing and the listing number in the subject of the email.
It comes directly from the person responding, and not through the qth.com 
server, so you can reply directly back to that email to start a conversation 
about your listing.
I'm not sure if EHam uses this method, but I suspect it does...same with 
Kijiji and ebay more or less.

73
Colin, V A6BKX
----- Original Message ----- 
From: "Ed Malmgren" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, June 01, 2011 10:07 AM
Subject: Re: Question about checking responses to ads placed on qth.com and 
eham.net


> Tom, you should be getting E-mails from interested parties but they may 
> come
> through the site where you listed the item.  I forgot for sure how it 
> works.
> Ed  K7UC
> ----- Original Message ----- 
> From: "tom behler" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, June 01, 2011 8:47 AM
> Subject: Question about checking responses to ads placed on qth.com and
> eham.net
>
>
>> Hi, all.
>>
>> Can someone tell me how you know someone has responded to an ad you have
>> placed on either qth.com or eham.net?
>>
>> I am hoping the responses are  via e-mail, so I don't have to keep
>> checking
>> the given web site.
>>
>> I just don't want to miss any responses I might get to my TS480 sale ad.
>>
>> I just checked, and, for some reason, my account on eham.net still hasn't
>> been approved, so I can't place my ad there yet.
>>
>> I'll give it a day or so here, and if I'm still not good by tomorrow, 
>> I'll
>> start checking into why.
>>
>> Thanks, and 73 from Tom Behler:  KB8TYJ