<s>
Sparrow	B-Application
was	O
an	O
email	B-Protocol
client	I-Protocol
for	O
OS	B-Operating_System
X	I-Operating_System
and	O
iOS	B-Operating_System
.	O
</s>
<s>
After	O
a	O
4-month	O
beta	O
period	O
,	O
Sparrow	B-Application
went	O
on	O
sale	O
in	O
the	O
Mac	B-Application
App	I-Application
Store	I-Application
on	O
February	O
9	O
,	O
2011	O
and	O
became	O
the	O
top	O
paid	O
and	O
top	O
grossing	O
app	O
in	O
less	O
than	O
one	O
day	O
.	O
</s>
<s>
On	O
July	O
20	O
,	O
2012	O
,	O
the	O
company	O
announced	O
that	O
it	O
had	O
been	O
acquired	O
by	O
Google	B-Application
and	O
was	O
ceasing	O
continued	O
development	O
of	O
the	O
application	O
except	O
for	O
critical	O
bug	O
fixes	O
.	O
</s>
<s>
Sparrow	B-Application
uses	O
a	O
simplified	O
user	B-Application
interface	I-Application
reminiscent	O
of	O
Twitter	B-Application
clients	O
such	O
as	O
Tweetie	B-Application
or	O
iOS	B-Application
apps	I-Application
,	O
as	O
opposed	O
to	O
a	O
more	O
traditional	O
email	O
style	O
such	O
as	O
Apple	O
's	O
Mail	B-Operating_System
or	O
Mozilla	B-Application
Thunderbird	I-Application
.	O
</s>
<s>
Sparrow	B-Application
currently	O
works	O
with	O
Gmail	B-Application
and	O
Google	B-Application
Apps	I-Application
accounts	O
,	O
along	O
with	O
other	O
IMAP	B-Protocol
email	O
accounts	O
.	O
</s>
<s>
It	O
also	O
includes	O
features	O
such	O
as	O
drag-and-drop	O
attachments	O
,	O
Dropbox	B-Application
or	O
Box.net	O
support	O
for	O
uploading	O
attachments	O
,	O
Growl	B-Operating_System
support	O
,	O
Gmail	B-Application
labels	O
and	O
keyboard	O
shortcuts	O
,	O
as	O
well	O
as	O
quick	O
replies	O
,	O
threaded	O
replies	O
and	O
easy	O
switching	O
between	O
accounts	O
.	O
</s>
<s>
In	O
March	O
2012	O
,	O
Sparrow	B-Application
for	O
iOS	B-Operating_System
was	O
released	O
in	O
the	O
App	B-Application
Store	I-Application
.	O
</s>
<s>
On	O
July	O
20	O
,	O
2012	O
,	O
Sparrow	B-Application
and	O
Google	B-Application
jointly	O
announced	O
that	O
Sparrow	B-Application
had	O
been	O
purchased	O
by	O
Google	B-Application
and	O
the	O
company	O
's	O
employees	O
would	O
be	O
added	O
to	O
their	O
Gmail	B-Application
team	O
.	O
</s>
<s>
Due	O
to	O
this	O
,	O
they	O
also	O
announced	O
that	O
development	O
of	O
both	O
of	O
Sparrow	B-Application
's	O
apps	O
would	O
be	O
ended	O
except	O
for	O
critical	O
bug	O
fixes	O
.	O
</s>
<s>
Sean	O
Gallagher	O
of	O
Ars	O
Technica	O
wrote	O
he	O
was	O
concerned	O
for	O
the	O
app	O
's	O
future	O
given	O
Google	B-Application
's	I-Application
previous	O
history	O
of	O
buying	O
out	O
and	O
subsequently	O
abandoning	O
development	O
on	O
other	O
startups	O
such	O
as	O
reMail	O
,	O
Meebo	B-Protocol
and	O
Quickoffice	B-Application
.	O
</s>
<s>
Rafe	O
Needleman	O
of	O
CNET	O
wrote	O
that	O
the	O
purchase	O
combined	O
with	O
the	O
ceasing	O
development	O
of	O
Mozilla	B-Application
Thunderbird	I-Application
meant	O
there	O
was	O
a	O
growing	O
lack	O
of	O
quality	O
desktop	O
mail	B-Protocol
clients	I-Protocol
.	O
</s>
<s>
However	O
,	O
TIME	O
noted	O
that	O
the	O
acquisition	O
may	O
lead	O
to	O
better	O
apps	O
for	O
Gmail	B-Application
.	O
</s>
<s>
Adrian	O
Covert	O
of	O
Gizmodo	O
expressed	O
excitement	O
about	O
a	O
possible	O
official	O
desktop	O
client	O
for	O
Gmail	B-Application
.	O
</s>
<s>
In	O
2014	O
,	O
Google	B-Application
released	O
Inbox	B-Protocol
by	I-Protocol
Gmail	I-Protocol
,	O
an	O
email	O
app	O
with	O
functionality	O
similar	O
to	O
Sparrow	B-Application
.	O
</s>
<s>
Inbox	O
was	O
shut	O
down	O
by	O
Google	B-Application
on	O
April	O
2	O
,	O
2019	O
.	O
</s>
