According to some sources, Twitter could see its 500 millionth registration sometime later today.

RAAK Social Media initially reported that the figure should become a reality on Saturday – though it is now believed that we could witness user number 500 million as early as this evening. Some industry experts are even suggesting that the microblogging site will see 1 billion members next year.

Analysing Twitter’s registration history, RAAK’s Adrian Pelzer wrote: “Two moments in the growth of Twitter stands out. Around March 2007 it had its first major spurt in registration rates when it won to great excitement the SXSW web award.

“Then, two years later, in March 2009 it had what is often called its hockey stick moment – and accelerated dramatically for a second time.

“From then the registration rate has slowly but surely accelerated even further. There are no more major surges in registration, even the Twitter integration in Apple’s millions of iOS devices have not created a clear new inflection point.

“But the ever faster trend in constantly bearing upwards is a glorious bending arch.”

Sceptics point out that Twitter revealed a 100 million strong active member base back in September 2011, and that the word active is key. April of last year saw the last time Twitter revealed how many registrations it has, citing 200 million. Another 300 million users in 10 months is phenomenal going for the site, but Pelzer’s upwards bending arch would be very steep indeed.

Twitter has declined to verify its prospective 500 million users, and also declined to comment on the methodology used to predict the trend. However, 500 million users is certainly something to celebrate, so let’s hope that Twitter make an official announcement whenever that landmark is reached.