You should register wordlensapp.com or something of the like. I'm not sure hosting nothing but the app promotion on a site with a completely different URL is beneficial.
With such a product, you should perhaps brand yourself more on your product than your company name. :)
There are many trends for using domains similar to what you would desire: get<product> being the best, and <product>app being one of the other choices.
I have very bad experiences with finding an app's site, if it models <product>app. Maybe it's just bad SEO on their part, but I imagine that it'd be an awful hassle for any normal user who don't know the conventions.
Then it struck me that <use>product would be a very interesting domain that makes much more sense than <product>app. It also mirrors the imperative <get>, although it may not be as popular and known to users - yet.
I think it's a shame they didn't secure a regular <product>.com domain for such a great product - but, on the other hand, I'm sure all the press will forgive them (hell, they're trending on Twitter, and 80% of my social media digest today was about the bloody thing).
I've registered usewordlens.com, usewordlens.net, and usewordlens.org and will be happy to hand it over or point it to a domain of their choice (if someone tells me how the hell to do it using name.com, because I'm a complete idiot in that regard. I guess I have to mess with some DNS).
Since you mentioned this, I registered wordlens.co and set it to redirect to their website. I emailed the info and asked them if they want it. That's how awesome I think this app is - I'd rather spend my own money to make sure they get a good domain.
otaviogood or johndeweese, if you're reading this, my email is in my profile.
With such a product, you should perhaps brand yourself more on your product than your company name. :)
Just throwing it out there.