I don't claim to be an SEO expert so just give me an example of how .tel domains are being improperly indexed by Google or anybody else and we'll see if there's a solution.
Do I need to teach you SEO ?
By contents I mean text, relevant text. Articles with the right keyword density and other extras are one example of content.
.tel has not contents, just data.
As for the HTML structure:
Let's have a look at the source code of sex.tel for example.
The title tag says nothing meaningful about your .tel. Yet it's one of the most important tags for SEO purposes. META tags are missing as well. If you want to see how it shows up in search results just type this query in google: site:sex.tel
It's clearly unoptimized, untargeted code. It's definitely not SEO-friendly and that's a
fact, not an opinion. You would really need a lot of quality backlinks to offset the lack of meaningful content. SEOing .tel just makes no sense.
Furthermore, branding of your domain is difficult since the .tel logo and the cookie-cutter layout takes over. The .tel branding is overwhelming.
Again, I perfectly understand that .tel was not designed for the web. So these are moot points in some way, but the fact remains that .tel is the absolute worst TLD you can get for SEO purposes. It's inferior to any other TLD, the only comparable extension being .arpa.
Just treat .tel for what it is - a data repository. Anything further is speculation.