"Sign Up" solves a problem for the site owner. Write something which solves a problem for the customer.
I'm going to try things like, e.g., Start Making Bingo Cards.
I actually had a few dozen buttons made in a particular design to test different calls to action against each other earlier this year, but the design itself flopped -- hugely -- against my pre-existing buttons, so much so that I didn't think color or copy changes on it would recover the loss. Curses on having my testing bandwidth limited by graphical expertise...
Though actual result will depend on A/B test, my experience suggests that this could be a double-edged sword. The call to action on my homepage said 'Start Optimizing Your Website Now' and some of the savvy users complained they couldn't find how to sign up. Some users simply wanted to sign up and my call to action looked like they had to go through additional pages before they get what they were looking for.
You could easily put a small "sign up" link in the header and/or footer that are not part of your "pitch" to the customers. Most "savvy" users I know are likely to search the page for something like "sign up" if they're looking to the point.
I think it depends of your target audience , people doing A/B testing are tech savvy enought to signup and spot a trial from a free offer, so it may not make much difference for them as they know what they are looking for, but if you are selling an ebook or a Bingo software, chances are your audience isn't tech savvy, so you can really tailor the message the way they understand it. So I'll say talk geek language to geek audience, they will get it, and avoid talking Geek language to non Geek audience, that's probably one of the main problems, geeks tend to talk geek language to non geek audience for non geek products. I think trial period or demo...etc means something for a geek, but probably not much for a non Geek, at the other hand, a non geek understand: free for 3 months, or try it for free and you pay nothing...I'll start some experiments for my eBook and report.
You can use a different version for people who uses Chrome/Iron (I think most chrome users are tech savvy). For other browsers you can use some other filter mechanism (like referrer).
If Chrome users are like me, a lot of Chrome users were set up by other Chrome users who fixed their computer, deleted the IE shortcuts from Desktop and Quick Launch bars, and renamed the Chrome shortcuts to "Internet".
I'm personally far more likely to click something like "Start Making Bingo Cards" -vs- "Sign Up Now" because it feels more like a call to action, not a call to fill some stuff out, then do some action.
I'm going to try things like, e.g., Start Making Bingo Cards.
I actually had a few dozen buttons made in a particular design to test different calls to action against each other earlier this year, but the design itself flopped -- hugely -- against my pre-existing buttons, so much so that I didn't think color or copy changes on it would recover the loss. Curses on having my testing bandwidth limited by graphical expertise...