According to Spamhaus.org, 80% of spam received by North American users comes from as few as 100 spammers. The company maintains the Register of Known Spam Operations (ROSKO), a database listing spammers who have been kicked off of at least three ISPs.

Smartphones and tablets drove 20.6% of e-commerce traffic during the fourth quarter of 2012, according to Monetate's Q4 2012 quarterly e-commerce report. PCs delivered the highest conversion rates at 4.45%, followed closely by tablets at 3.98%. Smartphones lagged at a 1.21% conversion rate. Smartphones however led in average order value, at $113.95. Tablets and PCs followed at $104.30 and $98.72 AOV respectively. 

To-do list manager Astrid now integrates with Gmail, turning emails into items in a comprehensive to-do list. The extension adds a button on the Gmail tool bar for "Remind me" which adds emails to the to-do list.  

Sailthru, an email startup that helps clients deliver personalized shopping offers and content to the inbox, has landed $19 million in Series B funding led by Benchmark Capital. The company will use the funds to expand its staff and infrastructure. 

The email hack over the weekend that exposed personal emails and photos about the former presidents George H.W. Bush and George W. Bush did not access the email accounts of the ex-presidents themselves, but instead infiltrated the accounts of six other people connected to the family, ostensibly to obtain information about the the ex-presidents. Unlike many high-profile hacks, this was not born from espionage or extortion, but from a desire for bragging rights.

The Next Web is currently developing a service called Inbox Pro which turns the problem of inbox overload back onto email senders. Each sender receives an auto-response informing him of the number of messages currently in front in the queue, and the approximate wait time before his message is answered. He is also provided a link to a page where he can categorize the message as either a Yes/No Question, FYI, Short Message or Long Message, each of which updates the queue accordingly. The service also includes an Expire function, which alerts the sender that his message was not read …

Emails opened in Gmail accounts have increased 25% over the past year, according to a new report by Litmus. Hotmail and Yahoo have each dropped 4% during the year. The report also finds that Outlook.com, which just launched late in 2012, was responsible for less than 1% of email opens.

SlickText.com has announced a new analytics dashboard for its SMS marketing platform. The dashboard reports on location, date, time and source of opt-in, and also tracks open rates, click-through rates, and subscriber activity following each text.

The most recent Return Path Email Intelligence Report finds that email read rates were below 17% worldwide during Q4 2012, down slightly from 2011. While some industries performed well (such as finance at a 27.5% read rate), others were below the average. Notably, only 15% of shopping emails were read during the quarter, down from 17% the year before. Return Path attributes the decline to subscriber fatigue due to an increase in volume.

Social conversation and collaboration platform Unified Inbox announced this week its definitive agreement to acquire HelloInbox, an app to check and send email and social network messages on an iPhone. The acquistion is expected to give Unified Inbox more expertise in mobile. The Unified Inbox platform is cloud-based and accessible via mobile or desktop.