<s>
MailBlocks	B-Application
is	O
an	O
e-mail	O
hosting	O
service	O
company	O
based	O
in	O
the	O
United	O
States	O
,	O
originally	O
established	O
by	O
Phil	O
Goldman	O
in	O
2002	O
.	O
</s>
<s>
Mailblocks	B-Application
offered	O
free	O
challenge-response	O
spam	O
filtering	O
web	O
email	O
service	O
and	O
an	O
IMAP	O
interface	O
as	O
a	O
revenue	O
service	O
.	O
</s>
<s>
Mailblocks	B-Application
did	O
not	O
invent	O
challenge	O
response	O
to	O
block	O
spam	O
.	O
</s>
<s>
Mailblocks	B-Application
then	O
proceeded	O
to	O
patent	O
troll	O
several	O
other	O
companies	O
before	O
releasing	O
any	O
product	O
of	O
their	O
own	O
.	O
</s>
