5. Presence in the regions. Especially important for projects that "start" not from Moscow, but other cities of Russia. The launch of regional subdomains can increase traffic up to 2-5 times, for Moscow - by 50-100%. You can get acquainted with the methodology of regional promotion by looking at the video report with Rambler Data Driven SEO # 5.
A common situation when, at the request of the form [to buy furniture], the issuance for 50% consists of subdomains. To analyze the issue, you can use the tools for checking geo-dependency and getting the TOP-10 URL.