It is good for social promotion but sincerely there is no worth of short domains over search engines because its seem tough for a website to define content & keyword prospective from a domain!
Just pick a domain that is related to your website name and you earn the #1 ranking for your companies brand name then anybody searching your companies name will find your website first.
2word domains are easy to remember and hence its a good habit.. making a domain longer isnt a good idea
Two word domains offer great value in search engine optimization and should be targeted towards the product you want to sell.
I personally like short domain names, but if you see from SEO point go with easy to remember rich keyword domain names.
You will not improve your SEO having keyword into domain name unless you are do search using: inurl:domain.com
I also search short domains always but now its much difficult to have sensible and short domain names.