I've always wondered about this. I get that having fresh content would help you land a new customer, but it seems like once they consider you their go to sign company that they never go to your site. When they need a new sign they just email or call.
Well, whether or not it is useful to existing clients has more to do with if the content is really useful to them. If it is just more photos, more words, probably not going to visit again. However, if, and the keyword is if you can create something engaging about articles perhaps, something funny, etc... but something that is a real value, then people will come back.
There are ways of monitoring and tracking this interaction, though in the normal course of sign shop's day to day ops, no one is going to usually go this far. I sure haven't thus far.
Now, on another side of the same coin, is content that Google likes, and content other industry partners might want to link to or share. That is a whole other ball game, and is something that any sign shop should be engaged if they want to utilize the web to reach a national or at least larger audience.
Really two different routes, whether you're trying to engage clients or the industry.
My personal opinion is that if you can engage the industry it just give you credibility to clients, so you can kill two birds with one stone.
I think it looks great visually. I did find one tiny mistake just looking through a couple pages quickly: on the window decals page "Frosted Vinyl" has an extra space in front of it so it doesn't line up with the other paragraphs.
Edit: Just noticed one other thing: the last word on the legal industry page is only half spelled out. It says "differe" where it should say "difference."
Ah, I thank you for pulling out the magnifine glass!! Corrections made