Cookie Conundrum

This is a post for the techies but one which other developers might appreciate.

Cookies are key to Mippin - we use the cookies to help shape the service around your usage so you do not have to register to get the majority of the features. When those cookies do not appear, the service loses a lot of its personality. It still works nicely but it does not shape itself around you - always leading you back to a generic home page.

Our analysis of three of the most popular markets showed the following ratio of devices not supporting cookies:

South Africa - 4% unsupported
UK - 6%
and
US - 43%

The last number really took us aback and we have spent quite some time querying the data.

It raised more surprises. Usually in these types of analysis Nokia scores the most highly and Motorola much less so. But in this data there were a very high number of early (MIDP1) and Series 40 Nokia that have no cookie support, indeed far more as a percentage of those total devices from Nokia than from any other manufacturer (60% vs 45% for Motorola for example - though the total number from Motorola was around the same given its superior market share in the US - over 2 to 1).

We were able to isolate the instances predominantly to the networks of Verizon, Alltel and MetroPCS and began to wonder if the policies or infrastructure of those operators meant that cookies were purposely withheld. (For example, use of an older version of an Openwave gateway by O2 in the UK withholds cookies).

The apparent answer we found through a simpler means.

Each of the devices were returning detail of the browser in the user agent and for each of those devices using the Openwave browser UP.Browser versions 6.2.3.*.

We found that the cookies were withheld for this particular browser. We looked a bit closer and realised that this only occured when the URL has no sub-domain: a problem when we have been promoting http://mippin.com to cut out on the number of key taps for the end user.

The problem handsets successfully store the cookie with a domain name they understand i.e. .(dot)mippin.com, but when they return to mippin they cannot match the domain .mippin.com to our site mippin.com and don't send us the cookie.

Other browsers deal with this without issue and now we know what the issue is, we can deal with it too. So: for users on a number of Series 40, or the high volume Moto KRZR or RAZR from the US operators above, a remarkably improvement in Mippin will occur.

Phew!