Black list for account names or subdomains. Check for pluralized version of each, too, to be safe.

reserved_names.txt

about
account
action
activity
add
admin
administration
affiliate
api
app
application
archive
article
asset
atom
attachment
attend
attribute
auth
authentication
billing
blog
business
cache
calendar
campaign
cdn
change
client
compare
config
configuration
connect
connection
contact
content
create
delete
destroy
dev
dispatch
display
download
edit
email
enterprise
entity
error
event
external
faq
favorite
feed
follow
follower
following
forum
ftp
help
home
host
http
image
imap
index
info
information
internal
invitation
invite
javascript
job
key
list
log
login
logout
mail
mailing
map
master
message
mine
new
news
next
note
oauth
official
openid
organization
partner
path
payment
person
plan
pop
popular
post
privacy
production
profile
project
provider
record
register
relationship
remove
reply
request
response
rss
rsync
save
search
secure
security
service
session
setting
sftp
shop
show
signin
signout
signup
site
sitemap
spam
ssh
ssl
staging
static
status
stylesheet
subscribe
support
system
target
template
term
test
tour
translation
trend
type
unfollow
unsubscribe
uri
url
usage
user
widget
wiki
www
xauth
xfn
xmpp