Re: How do they know?
I no longer actively blog but tgat is where my WP admin is at too. Someone cracked into it earlier in the year somehow (I've never run the vulnerable plug-ins,maybe compromised one of the admin accounts).
Ended up locking it down by limiting access to the admin to my private VPN. Also deleted all other accounts(been 3 years since anyone other than me wrote articles), no issues since fortunately.