Someone from MNHQ might want to contact [email protected] (which hosts the website of this 'other' mumsnet, which has blatantly copied the logo and put "Christian mumsnet" instead of "mumsnet By parents for parents").
If you want to give them a fright, contact [email protected] (but I guess as they are based in Palo Alto, they won't see any e-mail much before 4pm Monday (8am local time).