<s>
Tlen.pl	B-Language
was	O
an	O
adware	O
licensed	O
Polish	O
instant	B-Application
messaging	I-Application
service	O
.	O
</s>
<s>
It	O
was	O
fully	O
compatible	O
with	O
the	O
main	O
Polish	O
Gadu-Gadu	B-Application
instant	B-Application
messenger	I-Application
.	O
</s>
<s>
The	O
communication	O
protocol	O
is	O
based	O
on	O
open-source	B-Application
jabberd	O
code	O
,	O
but	O
it	O
was	O
modified	O
significantly	O
,	O
making	O
it	O
incompatible	O
with	O
generic	O
XMPP	B-Protocol
clients	O
and	O
servers	O
.	O
</s>
<s>
Among	O
other	O
features	O
,	O
Tlen.pl	B-Language
allows	O
for	O
voice	B-Protocol
chats	I-Protocol
,	O
SMS	O
sending	O
and	O
video	B-Application
conferences	I-Application
.	O
</s>
<s>
The	O
versions	O
later	O
than	O
4.0	O
allow	O
for	O
creation	O
and	O
usage	O
of	O
plugins	B-Application
.	O
</s>
<s>
Since	O
then	O
more	O
than	O
130	O
plugins	B-Application
have	O
been	O
created	O
by	O
the	O
community	O
.	O
</s>
<s>
By	O
April	O
2008	O
there	O
were	O
more	O
than	O
1	O
500	O
000	O
registered	O
users	O
and	O
780	O
000	O
real	O
users	O
of	O
Tlen.pl	B-Language
.	O
</s>
<s>
Tlen	B-Language
is	O
also	O
integrated	O
with	O
the	O
o2.pl	B-Language
mail	O
system	O
,	O
which	O
allows	O
users	O
to	O
use	O
mail	O
in	O
three	O
domains	O
:	O
o2.pl	B-Language
;	O
go2.pl	O
and	O
Tlen.pl	B-Language
.	O
</s>
<s>
Tlen.pl	B-Language
automatically	O
checks	O
the	O
user	O
's	O
account	O
and	O
if	O
there	O
is	O
any	O
new	O
mail	O
,	O
it	O
displays	O
a	O
notification	O
on	O
their	O
screen	O
.	O
</s>
<s>
It	O
is	O
also	O
possible	O
to	O
connect	O
to	O
Tlen.pl	B-Language
from	O
the	O
Tlen.pl	B-Language
homepage	O
with	O
a	O
browser	O
.	O
</s>
<s>
Since	O
version	O
6.0.1.7	O
,	O
Tlen	B-Language
has	O
included	O
the	O
Tlenofon	O
plugin	B-Application
,	O
which	O
enables	O
VoIP	B-Application
functionality	O
for	O
the	O
client	O
.	O
</s>
<s>
Tlenofon	O
is	O
similar	O
to	O
the	O
Skype	B-Application
service	O
and	O
offers	O
low-priced	O
calls	O
to	O
Poland	O
and	O
other	O
countries	O
.	O
</s>
<s>
In	O
the	O
second	O
half	O
of	O
2009	O
,	O
Tlen	B-Language
7	O
Beta	O
was	O
published	O
.	O
</s>
