I’ll have to go back and check. But Zogby does conduct some online surveys which use scientific methodology, although still viewed with suspicion as you pointed out. So if it’s one of those I wouldn’t call it junk, but it’s fair to view it skeptically. However, I’ll leave it in, because that poll of all the ones I found was the most favorable (least unfavorable?) for Lautenberg.
Zogby does use “scientific methodology” for his on-line surveys, such as making sure that X% of the sample are registered Democrats and Y% are Hispanic, etc., but not only are the persons who answer the survey self-selected (those willing to receive e-mails from Zogby) but such persons routinely claim to belong to groups to which they do not belong (I, myself, answered Zogby’s on-line surveys in 2004 and 2006 claiming to be a Gore-voting Democrat from New Hampshire when none of that is true).