I see sites that launch recently and they already have around 10 customer companies logos on their page under Customers. Some of these are logos of fortune 500 companies. How do you pull off something like this? Seeing Sony or even Microsoft using your software should improve your conversions? I mean if big companies use your software then small guys can trust it too?
Third-party validation and testimonials are a consistently proven component of the sales process. This is especially true in new product adoption.
Many people assume that the "Sony"'s of the world would not allow/permit their logo to be used unless they were a customer. Usually they are right.
Most of us -- yes me too -- are influenced by the due-dilligence process these company's go through in the selection of vendors.
Whether it is third party celebrity testimonials to get us to purchase shoes, or endorsements in the political arena, the ticker on the bottom of the info commercial telling people how many more items are available, or the case studies of past client success that every real "service' company provides -- third-party validation and testimonials sell. In fact-- that is the entire "point" of the "fan" button on Corporate Facebook pages.
Start-up companies that "already" have these logos already had them as customers. They probably had them as beta customers. They probably secured those beta customers through personal connections of the principals based on past professional relationships.
What can you do?
You better ask permission before you google image search a logo and slap it on your site. Some clients don't want their logos on customer sites due to secrecy, non-disclosures, etc.
For instance we had a vendor that did some work for us. We're still using them and they do great work. They failed to ask permission to put our logo on their site and an ambiguous description of the work they did. They had to remove it because our client which the work was done for can't have this out there (even a hint) due to us and them being 1st movers in this space.
So as you wrap up project with the client ask for a testimonial and ask to put their info on your site. Most times they'll probably say yes. Oh, and ask them for a high-res image of their logo. Don't google image search it. :(
On the other side of Valien's valid comments, many companies are eager to have their logos seen in the world and they even have approved graphics for your use. Sometimes these logos are provided right from their websites. Other times you have to ask. So just ask them.