Not so long ago, Chinese government made a statement (source: People's Daily Online) about single national standard on mobile phone chargers sold in the country. They wanted to avoid waste and to lower costs: "Under the new standard, all mobile phones, regardless of the brand, will be able to share one charger with a USB access, allowing users to charge handsets through laptops. (...) China has almost 450 million cell phone subscribers, with up to 100 million replacing their phones every year. The chargers are often disposed of with the phones.". 

Although no deadline had been set to allow charger makers to adjust their production, they responded quickly - Nokia did it as well (it's worth to note that China is the first largest market for Nokia in terms of sales, India being the second).
At the time of writing, five S40 devices have microUSB port (models: 8600 luna, 6500 classic/slide, 7900 prism, 6555). Some of these devices use microUSB for all connection types (one port for charging, data connection and audio), some have 2.0mm charger connector, 2.5mm audio and microUSB for data. It seems that Pop Port is not needed anymore. One big question is when microUSB with charging capability will come to S60 - will it be S60 3rd FP2 or later? The answer will come soon. Till then owners of devices with 2.0mm connector can use a special charger via USB (Nokia USB Charger CA-100).

I also have an idea - it would be interesting to use (micro)USB port in smartphones like we use in PC's. Just imagine connecting 'normal' PC's keyboard, mouse or additional flash memory to your smartphone through USB (is it a matter of proper device driver written for Symbian?)... one step in this direction is audio (which works directly through microUSB + headset HS-82 or AD-55 adapter).