The post which is nearly forgotten in Russia is an essential part of everyday life in UK.
When you shop online your orders are delivered by post, not by third-party couriers even within the city (actually, post is the last option when doing same thing in Moscow). When you apply for some government or private service in many cases documents can be sent by post too without visiting the office. Your mobile operator sends SIM card to you in the envelope and so does your bank with your credit card. Your postcode is an obligatory field in the majority of personal web forms.
In other words, Royal mail is something people really use.
As to mobile communications, there are differences too. Most of the Russian people use pre-paid (or Pay As You Go as they say in UK) plans for their mobile phones. Here in UK it is for newcomers and tourists with most Britons using credit plans and paying monthly. One of the consequences is that you can't top up your account as easy as it can be done in Russia, i.e. using one of the numerous terminals, ATM or any nearest shop. In UK, you can't top up simply telling or entering your mobile number - you must have a special magnetic card with you that is associated with your number and is read to gain access to payments.
You can still top up with cash in some shops showing special signs or in the branches of your provider (don't forget your access card!) but often you can top up only with amount multiplying 5 pounds - i.e. 5, 10, 15 and so on, no way stations.
Of course, you don't have all those problems if you have local credit card - if you do, you can use any ATM for it or pay online (much easier than in Russia), or even set automatic withdrawal from your bank account as you run out of money (in three clicks again). The thing is that when you have all the necesary credentials to obtain a card from local bank, you don't need Pay As You Go system because Pay Monthly is also available for you.
Unfortunately I don't have much to say about internet yet but I will next week.