I've noticed a couple approaches to managing unqualified Leads within the AppExchange ecosystem of eMarketing solutions.
One approach is to keep unqualified Leads out of Salesforce until they are "primed" and ready for some sort of phone call or personal interaction.
The other approach is to utilize features like Web-to-Lead and store all Leads, qualified or not, and modify the View visibility so that Sales people only see Leads that have matured past a certain milestone.
I highly prefer and recommend the latter approach and here is why: You may be having a qualified "dialogue" with these leads through your web site and not even know it.
Web Leads may be posting questions to discussion forums, commenting on blog posts, searching your knowledge base, or having live chat discussions with operators. In each case, you'll want a Lead record in Salesforce to capture and associate with these types of portal dialogues.
With i-Dialogue drip campaigns, suspect Leads may need to be touched with an email message once a month for several months before they register your solution with their problem. Drip campaigns are designed to gradually gather little pieces of information over time, instead of requiring one long registration form or survey. Therefore, it pays to be patient with these Leads and "let them ride" in Saleforce CRM for several months.
Just be sure not to unnecessarily expose your actual Salesforce and partner channels to these Leads.