At a time when investors are looking for eBay's (NASDAQ:EBAY) transformation to begin showing signs that it is working, the company delivered lukewarm results -- at least when measured against recent performance and expectations. Revenue came in lower than expected and guidance failed to impress.

But the quarter also had some strong points, including higher-than-expected non-GAAP earnings per share and solid growth in active buyers. Here's an overview of some key takeaways from the quarter in seven insightful metrics. 

eBay offices in Dublin, Ireland

eBay offices. Image source: eBay.

1. A 9% increase in revenue

eBay's second-quarter revenue was up 9% year over year, rising to $2.58 billion, coming in below a consensus analyst estimate for revenue of $2.66 billion and under management's guidance range for revenue between $2.64 billion and $2.68 billion.

Though eBay's 9% revenue growth was a meaningful deceleration compared to eBay's 12% growth in the first quarter, the deceleration wasn't nearly as significant on a foreign exchange neutral basis. By this measure, eBay's revenue was up 6% year over year compared to 7% growth in Q1.

The 6% growth in foreign exchange neutral revenue was at the low end of management's guidance range for 6% to 8% revenue growth.

2. A 25.2% non-GAAP operating margin

This compares to a non-GAAP operating margin of 26.4% in the year-ago quarter. On a GAAP basis, eBay's operating margin narrowed from 19.8% in the year-ago quarter to 15.4% in the second quarter of 2018.

Outsize growth in eBay's sales and marketing, product development, and general and administrative expenses compared to revenue growth weighed on the company's operating margin.

3. A 17% increase in non-GAAP earnings per share

eBay's earnings per share was still able to grow faster than revenue, despite a narrower operating margin than in the year-ago quarter. This was due to a lower non-GAAP effective tax rate. eBay's non-GAAP effective tax rate in its second quarter of 2018 was 13.3%, lower than a 19.9% rate in the year-ago quarter.

Non-GAAP EPS for the quarter was $0.53 -- above a consensus estimate for $0.51. 

4. $1 billion worth of common stock repurchases

The $1 billion stock buyback for the quarter was identical to what eBay spent buying back shares in Q1. While eBay's share repurchases during the quarter suggest management believes shares are undervalued, it's interesting that repurchases weren't higher. After all, shares traded at lower levels for most of Q2 compared to Q1.

5. 175 million active buyers

This was up from 171 million active buyers in the first quarter of 2018 and 167 million in the year-ago quarter. The key metric was up 4% year over year -- in line with growth seen in Q1 but down from 5% year-over-year growth in active buyers throughout 2017. 

While management has said it wants to improve its active buyer growth, it has also acknowledged that it will take time for its efforts to take hold.

6. Guidance for full-year revenue between $10.75 billion to $10.85 billion

This guidance range is down from a previous forecast for revenue between $10.9 billion and $11.1 billion. Furthermore, eBay also lowered its outlook for full-year revenue growth on a currency neutral basis. Management said it now expects currency neutral revenue growth between 6% and 7% -- down from a previous forecast for 6% to 8% growth.

Overall, eBay's results put the spotlight on a slowdown -- whether this slowdown is temporary or here to stay is what investors will have to watch for. The company's year-over-year currency neutral revenue growth decelerated and came in at the low end of guidance while management also reduced its expectations for the key metric's full-year growth rate. Of course, investors shouldn't read too much into a single quarter's results. But the pressure will certainly be higher in the second half of the year for management to deliver on its targets. If results continue to come in at the low end of forecasts, it could be a sign of bigger problems.

Daniel Sparks has no position in any of the stocks mentioned. The Motley Fool recommends eBay. The Motley Fool has a disclosure policy.