what are the downsides to a nonsensical domain name?

I'm sure there are some downsides, but from a Trademark perspective they are really good. The less descriptive your name and more unique your name is, the stronger the trademark will possibly be if you eventually file for a trademark with the Trademark Office. In fact, if it is 'merely descriptive' it isn't really eligible for a trademark.

Sure, there is a downside to anything ;)

Descriptive names can be great for search engine optimization. Having something like domainnames.com is better than godaddy.com for selling domain names for SEO purposes and you know what they do by hearing / reading it.

But I wouldn't get a domain name like iwanttobuyadomainname.com because the compounding and there is 0 cool factor, 0 brand and not really memorable.

Google, GoDaddy, (million other companies) could have got something descriptive, but made something fun and created their own brand.

Certainly downsides, but if you have a cool, fun, original name that will stick with people then run with it!

I think everyone has offered some great points and I think a creative name is definitely the way to go. My only caution would be to make the spelling of your domain name fairly phonetic. You don't want a unique/nonsensical name that no one knows how to spell.

There could be a chance (however remote) that a nonsensical name in one language could actually have a meaning in another language. If luck would have it, that meaning could even turn out to be embarrassing ... so you need to watch out for that

There are two factors of any website's popularity and high traffic rate:

1. Search Engines
2. Users

Yes, there are downsides of not getting a keyword optimized domain name. Search engines see the domain names as the first factor while indexing.

You may focus on making your website search engine friendly by obtaining a seo optimized domain name, but at the same time, you need to focus on your users as well.

There are many ways other than just the domain name, to get your website indexed on the first page of google and popular among your users as well.

A domain name is one the fundamental section that can certainly help your website to gain good search engine rankings, driving traffic and generating sales. If your website is new then choosing a sensible or keyword-based domain name is advised because it will get you many Search Engine and Brand-Awareness benefits by employing very minimal online marketing efforts. But if you have firm believe that your products are niche and will attract visitors with minimal marketing efforts then you can choose semi-sensible domain name as well. Because in that case, your products will promote your domain name and people will start knowing your domain name through your products.